Pre-focus type light bulb mounting



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L. T. FUQUA PRE-FOCUS TYPE LIGHT BULB MOUNTING Filed Aug. 29. 1952 INVENTOR ATTORNEYS United States Patent Lloyd T. Fuqua, Fortville,

Motors Corporation, Delaware Application August 29, 1952, Serial No. 307,027 1 Claim. (Cl. 240-41) Ind., assignor to General Detroit, Mich., a corporation of This invention relates to an incandescent lamp bulb mounting and more particularly to a mounting for a prefocus type bulb wherein a locating ring is used on the bulb socket to permit greater accuracy in the location of the lighting filament on the focal point of the reflector in which it is mounted. It is an object of this invention to provide a pre-focus type incandescent light bulb mounting which is simpler in construction than the conventional mountings in use today and which is therefore more economical to manufacture. Another and more important object of the invention is the provision of a pre-focus bulb mounting which requires less space particularly in that the overall length of the mounting device is much shorter than those conventionally used. These and other objects and advantages are carried out in accordance with the invention by the provision of a pre-focus mounting utilizing an insulator disk which surrounds the light bulb socket and from which extend inwardly the electrical connectors necessary to establish electrical contact between the lamp bulb filaments and the electrical circuit from which the electrical power for the light is derived.

In the drawing:

Figure l is a cross-sectional view of an automobile fog and turn signal lamp utilizing the improved lamp bulb mounting of this invention;

Figure 2 is a rear view of the mounting taken on the line 22 of Figure l Figure 3 is a perspective view with parts broken away of the lamp reflector casing and bulb mounting structure; and

Figure 4 is a front view of the mounting taken on the line 44 of Figure 1.

Referring now to the drawing, indicates the base of an incandescent lamp 12 which may be provided with one or more filaments as is common in the automotive lighting practice. The bulb is mounted in a lamp casing 14 provided with a lens member 16. The rear wall 17 of the casing in which the bulb is mounted may be a reflector member as is the case in the embodiment shown. The base 10 has brazed or otherwise suitably secured thereto a locating ring 18 having a series of three bayonet slots 19 formed therein. An aperture 20 of suflicient size to allow passage of the bulb base 10 is provided in the reflector casing 17. The locating ring is adapted to seat against the reflector casing portion 21 adjacent the aperture, the bulb base 10 extending through the aperture 20 as shown. Slots 22 extend outwardly from the aperture to receive the bulb securing means as hereinafter described.

The locating ring is secured to the base of the lamp bulb in accurate relationship to the filament or filaments and thereby avoids errors which might otherwise occur by reason of improper location of the filaments during the course of manufacture. With the filaments accurately located with respect to the ring and the ring accurately located on the reflector by seating against the reflector portion as described it is apparent that the bulb is properly positioned in the reflector when it is seated.

2,734,994 Patented Feb. 14, 1956 The mounting for the bulb 10 includes an insulator ring 24 made of laminated cloth and plastic such as Bakelite or some other suitable insulating material, to which are mounted a pair of upwardly and then inwardly extending electrical contact blades 25 and 26 made of some suitable highly conductive metal such as copper. Each of these electrical contacts 25 and 26 consists of a base portion 28 which is riveted or secured in some other suitable manner to the insulator ring 24 and a spring blade portion 29 which first extends outwardly from the periphery of the ring 24 and is then curled inwardly or back into generally parallel relation with the ring 24 so that its free end is adapted to abut a contact button 40 on the base of the lamp bulb when it is inserted into the mounting. Such a curled blade contact is advantageous in that it allows the use of a greater length of spring blade in the area available. In the particular embodiment shown, the incandescent lamp bulb has two filaments and is therefore provided with a pair of contact buttons 40. Therefore, a pair of spring contacts must be used in order to establish the necessary number of electrical circuits, each of the ing as is the conventional practice. However, it is to be understood that if a single filament bulb were used thereby requiring only one contact, only a single spring blade connector would be needed. Electrical conductors 31 and 33 are secured to the respective contact elements 25 and 26 and establish electrical connection with an electric power source for the lamp.

The means for mounting the insulating ring 24 to the reflector casing 17 consists of a number of circumferentially spaced pins 30 having enlarged conical heads 32, the heads being seated in the respective slots 22 in the reflector. The pins 30 pass through apertures in the insulator ring 24 and are secured thereto by heading over their end portions as shown at 34. Spiral springs 36 surrounding the shanks of the pins 30 urge the insulator ring 24 away from the reflector 17 and hold the bulb locator ring 18 tightly against the reflector 21 when the bulb is in place. For convenience in assembly, two of the pins 30 are connected adjacent their conical heads with an elongated curved washer 35 while a single washer 38 is secured to the other pin in a like manner. The elongated washer 35 facilitates assembly by holding two of the pins 30 in proper position for engagement with the slots 22.

To insert the insulator ring and pin assembly into the reflector casing the conical heads 32 of the two pins 30 connected by the elongated washer 35 are first seated in slots 22. To do this it may be necessary to tilt the pins slightly inwardly toward the reflector axis to engage the conical heads with the inner ends of the slots. They thereafter fit in the outer ends of the slots at which time the conical head of the third pin may be easily inserted into the remaining slot 22. With this assembly made, to mount the bulb 12 in the lamp casing it is necessary only to insert the lamp bulb with the enlarged portions of the slots 19 over the conical heads 32 of the pins 30 whereupon the bulb may be rotated to seat the heads in the smaller ends of the slots 19. When this seating is accomplished, the contact buttons on the base of the bulb socket will be properly aligned and in contact with the ends of the spring blade connectors 25 and 26. It will be noted that the pins 30 as Well as the slots 19 are unequally spaced about the circumference of the socket and thus, there is but one position in which the pins 30 will properly engage the slots 19. In this way, proper alignment of the contact buttons 30 with the connectors 25 and 26 is assured.

The mounting of this invention is particularly advantageous in that it requires less space behind the reflector for the electrical connector assembly. Thus, it is especially circuits being grounded through the reflector caswell suited for use in lamps having shallow casings or in lamps which are mounted in locations which afford only a small amount of room behind the reflector.

It is to be understood that, although the, invention has been described with specific reference to a particular embodiment thereof, it is not to be so limited since changes and alterations therein may be made which are within the full intended scope of this invention as defined by the appended claim.

I claim:

The combination of a reflector having a generally circular aperture and a plurality of smaller apertures arranged about the periphery of said generally circular aperture, a light bulb having a cylindrical base adapted to be inserted into said generally circular aperture and an an nular locating flange adapted to abut said reflector and having a plurality of openings adapted to register with said smaller apertures in said reflector, a flat ring of rigid nonconductive material positioned on the side of said reflector oppositely disposed from said bulb locating flange, ;a plurality of pins connecting said ring to said reflector, each of said pins having one end secured to said 'ring and the other end extending through one of said smaller apertures and one of said openings, said other end being provided with "aconical-head-to 'prevent unauthorized withdrawal of said pins from said reflector, a spiral spring surrounding each of said pins and interposed between said reflector and said ring to urge said ring away from said reflector, and a contact member secured to said ring said contact member having a spring blade portion extending outwardly from the periphery of said ring and then curled inwardly toward the center of said ring and into generally parallel relationship thereto to make electrical. contact with a contact button on the base of said light bulb.

I References Cited in the tile of this patent UNITED STATES PATENTS 1,300,360 Duffy Apr. 15, 1919 1,310,150 Woods July 15, 1919 1,386,412 Kroehle Aug. 2, 1921 1,770,724 Bamford July 15, 1930 2,219,770 Falge et a1. Oct. 29, 1940 2,471,190 Bartelson May 24, 1949 

